Ask an Expert: Dr. Kluger Discusses Cannabis Research and Parkinson’s

Dr. Benzi Kluger, MD, MS, is an Associate Professor of Neurology and Psychiatry, as well as the Chief and Founder of the Palliative Care Section at the University of Colorado. His research focuses on the non-motor symptoms of Parkinson’s, including fatigue and cognitive dysfunction. Taking a palliative care perspective, Dr. Kluger supports patients with advanced neurological illnesses in exploring novel treatment options like non-invasive brain stimulation and alternative medicine.

Many of Dr. Kluger’s patients have turned to cannabis to help treat their non-motor symptoms following legalization in Colorado in January 2014. Depending on the symptoms people wish to address, he helps them find the correct concentrations, doses and sources of cannabis and cannabis-based products.

It is important to note that cannabis cannot be considered a viable overall treatment for Parkinson’s. Instead, anecdotal evidence suggests it to be helpful in alleviating some symptoms. Each person will react differently to cannabis-based products, so be sure to consult a physician before trying cannabis as an alternative treatment.

What is cannabis?

Cannabis is the overarching genus of plants that includes sativa, indica and ruderalis. Sativa is a type of cannabis that has higher levels of THC, so people sometimes conflate sativa with THC, but it also contains other chemicals. Indica and ruderalis tend to have more Cannabidiol (CBD) than Tetrahydrocannabinol (THC).

What are cannabinoids?

Cannabinoids, as the name would suggest, are chemicals that can be derived from a cannabis plant. They act on cannabinoid receptors, which are specialized receptors in the nervous system and immune system. The two most common cannabinoids we talk about are THC and CBD. Now, there are over a hundred psychoactive cannabinoids that have been extracted from the cannabis plant. As you can imagine, it is becoming more and more complicated to try to understand what the effects of cannabis are, since there are so many chemicals in a cannabis plant.

How does cannabis affect the nervous system?

There is a lot of hype around cannabis for Parkinson’s disease; however, it is known that if you directly stimulate cannabinoid receptors, you actually decrease the production of dopamine. As a result, it is unlikely that cannabis and cannabis-based treatments are going to replace other medications for Parkinson’s. However, there are over a hundred different cannabinoids (chemicals) in cannabis, some of which stimulate cannabinoid receptors and others that block them or work independently of these receptors. How they are going to act also depends on the state of the nervous system. The bottom line is that there is more research needed to understand how best to utilize them in the context of Parkinson’s.

Do cannabinoids improve motor symptoms in Parkinson’s disease?

In animal models, the published studies are mixed regarding motor improvements. There have been a number of studies showing slowed movement in animals, and some that show faster movement. This is because the effect will depend on the type and dose of cannabinoid used.

I published a study in Colorado looking at people with Parkinson’s. Only 5% of people in our clinic reported using cannabis and of those, most reported that they found benefits mostly for non-motor symptoms. These would include things like sleep, anxiety, pain, nausea and appetite. The benefits for motor symptoms were much more variable. That being said, I have a few patients who are using cannabis and they feel like it helps smooth out some of their offs and ons and motor fluctuations, but that is really a minority of people I see in my practice.

When people have done other trials with a placebo control group, they have been unable to show that there is a benefit from cannabis. I would say, however, that rather than calling these results negative, they were inconclusive. It is possible that they did not find the right dose of cannabis or the right mix of cannabinoid concentrations in the plant. I think there really is more research to be done.

We are hoping to do a trial at the University of Colorado using high doses of CBD to see if that would help with tremor. I think the dosing is actually very important. If you compare the doses that we extract from the randomized control trials to the doses being used in epilepsy, there is a major difference. These trials use 5–10mg of CBD, compared to 50–100mg used for epilepsy.

Do cannabinoids improve non-motor symptoms in Parkinson’s?

There has been some interesting animal research regarding memory and cannabis. It was shown that CBD may actually improve memory and increase neuronal function and THC may improve memory in older mice, but not younger. If you look at the research on people, however, the oldest subject in any cannabis trial was 30 years old. So we have almost no idea what cannabis does in people over 30 despite the fact that this is now the largest growing population in terms of medical cannabis use.

There have been some case series which suggest there may be a benefit for REM behaviour disorder and for psychotic symptoms like hallucinations, delusions and agitation in people with either Lewy Body dementia or Parkinson’s disease dementia. Both of those were with CBD.

What is your advice to people interested in using cannabis to treat their symptoms?

When it comes to alternative medicines, there is no regulation on products. One thing I advise people is to find a dispensary that they know and trust, and to stick with that dispensary and their products. The second thing is to start with a low dose and go up slowly. A third thing is to try and tailor your use of cannabis to the symptoms you wish to treat. For example, in people who are having pain, often what we will do is start with a cream or a patch, which can be helpful for pain and tends to have less of the systemic side effects compared to oral or smoking products. THC seems to be best for nausea and appetite; so if those are the target symptoms, having a product with more THC than CBD would be helpful. On the flip side of that, for things like sleep, CBD might be more helpful than THC.

We generally recommend oral products such as drops or candies to avoid smoking, which can have effects on the lungs and vocal cords. The disadvantage of oral products is that a lot of the time, absorption is harder to predict in terms of timing as well as dosage. I do have some patients that will use a vape pen to get targeted hits to smooth out certain symptoms. We really want to make sure we are using the right product for the right symptom, and also that we have a target.

This content was published in the Fall 2018 edition of our quarterly magazine, Viewpoints. The content was accurate as of this publication date.